Is bov flutter when i shift at really low rpm's bad? with my stock IX bov it flutters a little bit and i swapped it to a forge bov and it flutters every shift if i dont hold my rpms till like 4k... if i wot it will open up at any boost over like 5 lbs but i drive really easy around town and i didnt know if it was bad for the car? why would it be if the stock one does it as well? (sometimes)

 

I have the same flutter with my hks bov if I don't go into boost and shift. Also wondering if this is bad for the turbo?

 

The flutter is back pressure against your turbo, which spools it backwards. This is very bad. I experienced this sometimes in my old evo with a turbosmart dual port.

If your driving around town and the such, try not to hit boost. Of if cruising on the highway. If you do hit boost, Just step on it completely for about a second so all the boost builds up, and let it go, to release it. The backpressure is killing the turbo.

Or, Buy a softer spring if available for your BOV.

Just my .02, based on my knowledge. Correct me if I am wrong about the softer spring, because there might be the possibility of it opening up during WOT if its to soft, and the boost going out aswell, :P

 

well i dont think it spins the turbo backwards.... otherwise i would know cuase back spool sound HORRIBLE! and i would know i heard it on a deisel once... i think that is what the wastegate on the turbo is for... so it doesnt have back spool? am i right?

 

I am not aware about the wastegate, but as far as I know with this as it happened to me, my mechanic explained to me it cuses the compressor to surge. It doesn't necessarily spin it basckwards completel,y that would be imposasible with the exhaust gases pushing the turbo, but it causes the air to basck onto it and surges it. This KILLS your compressor wheel, and may destroy your bearings ( correct me if im wrong).

Let it boost and release it, or get a softer spring.
I think it is moreover with just getting better at driving the car though. This is one of the things you have to learn about these and get the feel for. You'll get used to it. Just spool it out and release.

 

Fluttering is causing the turbo to spin backwards or halt, which is the same thing as compressor surge. The air is being redirected back into the path of the turbine.

I have bov fluttering with an oem 9 bov. Fluttering occurs when the turbo is, in essence, fighting between boost and vacuum.

As far as it being bad, I am unsure. I have read that as long as it is not major fluttering, there will be minimal effect on the turbo's lifespan.

 

With the boost going backward however, it does cause the compressor to surge. The "flutter" is the compressor surging backwards, is it not?

 

Also, do you have it VTA? If so that could be one of your issues as well.

 

The new Tial QR is working out for me. I know a couple of others have it installed and haven't reported any problems.

 

Can fluttering be removed through a tune at all?

 

Nope purely mechanical.

 

compressor surge is the air being forced back into the turbo. the turbo wheel doesnt actually spin backwards. its not good for the turbo at all, thats obvious, but most bov's that ive seen on evos will do this on low rpm/boost shifts. aftermarket bovs are adjustable, just make sure you get one that is, and wont cause a stalling out issue.

 

So surge is a cause of stalling issues with BOV?

 

I have the same sound on my stock DV and I think every evo does, you just can't hear it, I have a mod to my lid so I can hear it clearly. It's normal, won't damage anything, and BTW someone said it will damage the bearings (I suppose turbo bearing) well our turbos don't have those.

 

i know what back spool or compressor surge is but like i said... the stock DV does do this quitely and my forge does it the same if you get to about 0 lbs or into vacuum it has some flutter to it.

I run 21 lbs. with a tune and i cant use a softer spring cause it doesnt stay closed at wot and so i have to have the tighter spring in there but i just want to make sure it is not damaging the turbo.... majorly.... like i said the factory one did it so i can imagine it will not destroy it quickly